Curable silicone compositions have been used in a wide range of industrial fields since these curable silicone compositions cure to form cured products having excellent heat resistance, cold resistance, electrical insulating properties, weatherability, water repellency, and transparency. In particular, the cured products thereof are less likely to be discolored compared to other organic materials, and the cured products cause less degradation of physical properties. Therefore, the cured products are suitable as optical materials. For example, Patent Document 1 proposes a liquid silicone resin composition for light emitting diode (LED) elements, comprising: an alkenyl group-containing silicone resin, a silicon atom-bonded hydrogen atom-containing organopolysiloxane, and a hydrosilylation reaction catalyst.
Meanwhile, materials that are solid or semisolid at room temperature have been proposed for production process for novel LEDs in recent years. For example, Patent Document 2 describes a sheet-like silicone resin composition for light emitting diodes (LEDs), comprising: an alkenyl group-containing silicone resin, a silicon atom-bonded hydrogen atom-containing organopolysiloxane, and a hydrosilylation reaction catalyst. Patent Document 3 describes a curable organopolysiloxane composition comprising: a solvent-soluble alkenyl group-containing organopolysiloxane formed by a hydrosilylation reaction of an alkenyl group-containing organopolysiloxane and a silicon atom-bonded hydrogen atom-containing organopolysiloxane, a silicon atom-bonded hydrogen atom-containing organopolysiloxane, and a hydrosilylation reaction catalyst. Patent Document 4 describes a silicone resin sheet formed by partially curing a silicone resin composition comprising: an organopolysiloxane having at least two alkenylsilyl groups in a molecule, an organopolysiloxane having at least two hydrosilyl groups in a molecule, a hydrosilylation reaction catalyst, and a reaction inhibitor.
However, these materials have problems such as having surface stickiness at 25° C., having insufficient hot melt properties, and being not satisfactory for practical applications.